Scientists have found a rogue planet that acts like a star, gobbles up surroundings. Here's what we know

Like Earth, most planets outside our solar system orbit a star. But some drift through space all on their own, with no star to call home, these are known as rogue planets.

Their origins remain largely a mystery, yet astronomers have now observed a young, extremely active rogue planet that could offer new insights into how these solitary worlds form.

This planet, called Cha 1107-7626, is believed by scientists to be five to 10 times more massive than Jupiter, the largest planet in our solar system.

Here’s what we know about it so far.

What are rogue planets?

Most planets we know orbit stars, but rogue planets (or free-floating planetary-mass objects) roam the galaxy on their own, untethered to any star.

How they come into being is one of astronomy’s bigger mysteries. Some theories suggest they might form like stars, from collapsing clouds of gas, but never gain enough mass to ignite fusion. Others propose that they started around stars and got ejected by gravitational forces.

“How these objects form is still an open question,” said study co-author Belinda Damian, an astronomer at the University of St Andrews in Scotland.

Cha 1107-7626 gives weight to the idea that some rogue planets may follow a star-like birth path, going through growth bursts and accretion processes we typically associate with young stars

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What makes Cha 1107-7626 special 

Cha 1107-7626 is estimated to be five to 10 times more massive than Jupiter.

It was spotted amid a sudden burst of growth, at the centre of a disk of gas and dust. In that moment, it was gobbling up its surroundings in a way never before seen in a planet.

At its peak, during August of this year, it was consuming this material at a rate of six billion tons per second, about eight times faster than just a few months earlier.

Víctor Almendros-Abad, of the INAF Astronomical Observatory of Palermo in Italy, lead author of the study published this month in the Astrophysical Journal Letters, said, “The outburst we detected is extraordinary, being similar to some of the most intense phases of growth seen in young stars. It reveals that the same physical processes driving star formation can also occur on a planetary scale.”

He also noted: “This object is about one to two million years old. This is very young for astronomical standards.”

Though Cha 1107-7626 is still growing, scientists believe it won’t gain much more mass. It appears to have strong magnetic fields funnelling material from the disk inward, a process seen in stars but rarely in planets.

The researchers observed Cha 1107-7626 using the European Southern Observatory’s Chile-based Very Large Telescope. It is located in our Milky Way galaxy about 620 light-years from Earth in the constellation Chamaeleon. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).

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Why it matters

For the first time, we’re seeing a rogue planet caught in a stellar-style growth mode. That means the processes we once thought were exclusive to stars also operate, at least sometimes, in planetary realms.

“This is a really exciting discovery because we usually tend to think of planets as celestial bodies that are quiet and stable, but now we see that these objects can be dynamic just like stars in their nascent stages,” Damian said. “It sort of blurs the line between stars and planets, and gives us a sneak peek into the earliest formation periods of rogue planets.”

Now, with observations like this, astronomers can refine theories, explore how magnetic fields shape young planets, and maybe even reclassify how we see the boundary between planets and stars.

With input from agencies